Abstract
Self-propagating high-temperature synthesis (SHS) is a
widely known and extensively studied highly
exothermicreaction-utilizing technique for making certain
advanced composites and intermetallic compounds. However,
only few studies have been published about the SHS of
pure aluminosilicate ceramics. In the current work,
possibilities for aluminosilicate ceramic synthesis and
sintering requiring less energy based on the utilization
of SHS in air was studied. Kaolinite powder and
exothermically reactive metallic aluminium powder were
used as raw materials. Thermodynamic calculations for the
possible reactions and reaction paths were performed to
show the theoretical possibilities for SHS utilization.
The chemical reactions, thermal expansion behaviour and
formed phase- and microstructures after SHS were compared
to the conventional reaction sintering of mullite.
Results conclude that highly exothermic reactions above
900 °C relating mainly to aluminium oxidation can ignite
the SHS reaction in air atmosphere. After initialization,
the reaction proceeded in a self-sustaining manner
through entire test pieces, resulting in the formation of
an Al2O3 - Si phase structure. Thermodynamic calculations
showed the total energy balance for mullite formation
from aluminium and kaolinite mixtures as highly
exothermic in nature only if sufficient oxygen is
available to complete the reactions. However, future
research is needed to fully utilize SHS in
aluminosilicate ceramics processing.
| Original language | English |
|---|---|
| Pages (from-to) | 101-112 |
| Journal | Journal of Ceramic Science and Technology |
| Volume | 8 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Mar 2017 |
| MoE publication type | A1 Journal article-refereed |
Keywords
- aluminosilicate ceramics
- self-propagating high-temperature synthesis
- SHS
- exothermic reactions
- synthesis
- sintering